RALEIGH, N.C. (AP) -- Workers were dismantling a scaffold at a high-rise construction project when a piece of it fell to the ground in downtown Raleigh, killing three men and sending another to a hospital.

A section of scaffolding framework hangs from the side of the Charter Square building in downtown Raleigh, NC. (AP Photo/The News & Observer, Harry Lynch)

Jeffrey Hammerstein, community outreach chief for Wake County EMS, said three men died and a fourth was seriously injured in the accident at the glass and steel building called Charter Square in downtown Raleigh. All four men were involved in the construction project, Hammerstein said.

The accident happened around 11 a.m. as a subcontractor called Associated Scaffolding was in the process of dismantling the scaffold on the building's exterior, said Mike Hampton, the chief operating officer for the building's general contractor, Choate Construction Company. The equipment known as a mast climber scaffold rises up and down to take workers to different floors.

"We are finished using it. They actually were dismantling that piece when it happened," Hampton said. "It wasn't as if it was business as usual, they went to work and it collapsed."

Choate issued a statement saying the company is "deeply saddened by the loss of life and injuries."

Peter Thuston was working inside the building installing a security card reader system when the accident happened.

He said he ran outside to try to help and saw three men in safety harnesses, leading him to believe that they had been attached to the scaffolding.

"It was just a loud crash and a huge cloud of smoke," said Thuston, 32, of Garner. "I noticed three of the guys and it looked like they were dead."

He said a fourth man wearing a safety harness was found on a crushed portable toilet after apparently falling onto it. The man was still breathing and had a pulse, but was barely responsive.

Thuston said he had walked inside minutes before the accident.

"That could have been anybody. That could have been me," he said.

The scaffolding that fell was attached to the side of the new building. One of the tracks had snapped off several stories up and fallen into a twisted heap on the ground below.

State Department of Labor spokesman Neal O'Briant said his agency is investigating the cause. Officials had closed off a wide area around the scene.

A group of men in hard hats and yellow vests, some of which said Associated Scaffolding on them, were talking to an official near the edge of the police line. People who answered multiple calls at the company's Durham headquarters declined to comment.

Hampton said the subcontractor's only job at the site was erecting and dismantling the scaffolding.

Occupational Safety and Health Administration records show that Associated Scaffolding was issued serious safety violations twice in North Carolina in the past 10 years. A 2007 citation says it was related to access equipment for scaffold platforms, while a 2008 citation says the violation was related to storage of welding materials.

The records show that Choate Construction has been inspected 20 times in North Carolina in the past 10 years and cited for one violation, which wasn't considered serious. O'Briant said the 2014 violation was related to storing flammable materials outside without a fire extinguisher.

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